state.v file created

09_defer/log.txt

@@ -1,2 +1 @@
-asiofjasodifjasdfasdfasdfasd
-asdfasdfasdfasdfasdfasdfsadf
+This is a log file

09_defer/state.v

@@ -0,0 +1,41 @@
+import os { create }
+
+enum State{
+	normal
+	write_log
+	return_error
+}
+
+fn write_log(state State) !int {
+	mut f := create('log.txt')!
+	
+	defer { 
+		f.close() 
+		println('File closed')
+	}
+
+	match state{
+		.normal{
+			return f.writeln("This is a normal file")
+		}
+
+		.write_log {
+			return f.writeln("This is a log file")
+		}
+
+		.return_error{
+			return error('nothing written; file open: ${f.is_opened}')
+		}
+	} 
+	return 0
+}
+
+pub fn main(){
+	n := write_log(.write_log) or { 
+		println('Error ${err}') 
+		0
+	}
+
+	println('${n} bytes written')
+
+}